Arthritis is one of the most prevalent chronic health problems and one of the most common causes of disability in America. It affects over 45 million adults in the United States. This number is anticipated to rise to 60 million, or 18% of the population, by 2020. There are more than 127 different types of arthritis as defined by the Arthritis Foundation, including osteoarthritis, rheumatoid arthritis, psoriatic arthritis, septic arthritis and related autoimmune diseases. Regardless of the type of arthritis, common symptoms for all arthritis disorders include varied levels of pain, swelling, functional limitation and joint stiffness. Arthritic disorders such as lupus and rheumatoid can also affect other organs in the body.
The goals of current therapies for arthritis, including osteoarthritis, are to alleviate pain and other related arthritis associated symptoms. Current therapies for managing osteoarthritis pain include oral analgesics or corticosteroids, localized treatments with topical analgesics (e.g., NSAIDs, capsaicin), intra-articular injections of corticosteroids or viscosupplements. Oral analgesics have substantial limitations because they may not provide sufficient pain relief and often produce intolerable side effects, for example, gastrointestinal bleeding and renal toxicity for regular NSAIDs users, addiction or breathing suppression for opioids; and adverse drug interactions. Localized corticosteroid injections may reduce pain for a short period (1-3weeks), but have long term side effects, including cartilage break down, Cushing's syndrome; furthermore they are intolerable to patients with diabetic mellitus. Viscosupplement administration, such as hyaluronic acid, While well-tolerated, is not always effective. Thus, there is a need for safe, effective alternative therapies for treatment of osteoarthritis pain.